Clinical significance of epicardial pacing wire cultures

Routine cultures of epicardial pacing wires removed 5 to 10 days postoperatively were obtained in 205 adults who underwent cardiac operations through median sternotomy. The study was conducted in a double-blind prospective fashion in which clinicians were unaware of culture results. With the exception of 10 out-of-town patients who were followed up only until the day of hospital discharge, the patients were followed for at least 6 weeks (195 patients) for evidence of poststernotomy wound infections. Deep wound infection rate was slightly less than 1% in this patient population, with less than 0.5% having had superficial wound problems. Of the 205 patients, 27 had positive epicardial pacing wires cultures, with a total of 30 microbial isolates. Of 30 isolates, 26 were consistent with local skin flora (Staphylococcus, Streptococcus, Enterococcus, and diphtheroids). Wound infection developed in none of these patients. The remaining four cultures were of either Enterobacter or Serratia. In two of these four patients deep sternal infections developed. In the remaining 178 patients whose wire cultures were negative, no deep sternal infections developed. The fact that all clinically manifested deep sternal infections were associated with positive epicardial pacing wires cultures suggests that epicardial pacing wires cultures may be useful in the treatment of high-risk patients or of those in whom deep sternal infections are suspected.